In prior art barking tools, for example of the type described in Swedish Patent Specification 7712802-3, the screw connection between the pivot shaft and the holder frequently causes trouble. During operation, the swinging arms of the machine are under severe strain in the form of violent jolts, not only when the leading end of a log fed into the machine bumps against the arms to open them, but also when the arms after barking leave the trailing log end and are quickly swung back into their central initial positions. Unless the screws of the connection have been tightened with a specific and relatively large tensioning force, they will sooner or later work loose in their threaded holes, and the result is that also the swinging arm will sit loose on its holder and rattle. Furthermore, the lost gripping power of the screw detracts from the barking efficiency. In more serious cases, the arm may even break loose from the holder, with serious consequences to those standing around.